Wenger, the Arsenal manager, will step up his long-standing interest in Smalling as he prepares to recruit a new centre-half for next season.

Arsenal are aware that the England international will only have 12 months left on his contract at Old Trafford after this campaign and it is understood no talks have yet been held over an extension.

With uncertainty surrounding the future of Per Mertesacker, who could be moved on this summer, Smalling is emerging as an attractive target for Wenger as he will also boost Arsenal's homegrown quota.

Arsenal were beaten to the £10million signing of Smalling in January 2010 but Wenger has retained a strong interest in the former Fulham defender and is encouraged by United's delay in negotiating a new deal.

Louis van Gaal, the United manager, has also identified a new centre-half as a priority signing in the summer and is expected to intensify his attempts to sign Borussia Dortmund's Mats Hummels.

Dortmund have suffered an alarming fall from grace this season and are susceptible to losing Hummels, the Germany international. The potential sale of Smalling would accelerate United's attempt to sign Hummels, who will be available for around £35million.

United are also no nearer offering Smalling's defensive partner Phil Jones a contract extension, despite running the risk of losing him for a reduced fee this summer.

Louis van Gaal could move for Dortmund's Mats Hummels

Like Smalling, Jones' current deal expires at the end of next season and there has been no approach from United to his representatives at this stage.

Signed from Blackburn Rovers in June 2011 for a fee of around £17million, Jones also held talks with Chelsea, Liverpool, Arsenal and Everton before opting to play for Sir Alex Ferguson.

Injuries have undoubtedly damaged the 23-year-old's progress but his form over the last few months has impressed Van Gaal.

Seven other high-profile United players will be heading into the last years of their contracts next season, including goalkeeper David De Gea, Robin van Persie and Ashley Young.

United are understood to be relaxed about the situation of all the players and in no rush to initiate talks, but that approach is certainly a gamble with De Gea due to his growing status across Europe.